1. Field of the Invention
This invention relates to a developing device which is used in an image forming apparatus such as a copying apparatus or a printer and in which a toner cartridge is removably mountable.
2. Related Background Art
Many developing devices using cylindrical toner cartridges have become commercially available as developing devices for use in image forming apparatuses, particularly electrophotographic copying apparatuses. These cylindrical toner cartridges are easy to insert into the bodies of developing devices and are easy to rotate in the developing devices after the insertion thereof into the latter.
Now, a high sealing property is required of a toner cartridge containing a developer (hereinafter referred to as the toner) therein so as to prevent the toner from leaking out when the toner is supplied to a developing device. The reason is that the leakage of the toner out of the developing device would stain a user's hands or clothes.
It has therefore been practiced to mount the toner cartridge in the device body with the opening portion thereof which is sealed by a sealing material remaining turned upward, and peel off the sealing material, and thereafter rotate the toner cartridge so that the opening portion may face laterally, and when dismounting the toner cartridge, rotate the toner cartridge so that the opening portion may face upward so that any toner remaining in the toner cartridge may not spill, and thereafter pull out the toner cartridge.
An agitating bar for discharging the toner from an opening portion is provided in the toner cartridge, but when the driving construction of the agitating bar and the developing device has been simplified and the agitating bar and a developing sleeve have been connected together by gears and a driving load has been made small, the following problem has arisen.
When the toner cartridge is inserted into the device and is rotated, the agitating bar in the cartridge is also rotated therewith.
The rotation of this agitating bar causes the rotation of a driving gear train, which in turn causes the reverse rotation of the agitating bar and developing sleeve in the developing device and thus, the unsatisfactory conveyance of the toner and the unsatisfactory coating of the toner on the developing sleeve occur and unsatisfactory images are created.